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Recovery of Ammonia Energyfrom Municipal and AgriculturalWastewater: AmmoniaElectrolysis
Gerardine G. BotteAssociate Professor, ChE
Director Electrochemical Engineering ResearchLaboratory
John HolbrookDirector
AmmPower LLC
Ammonia the key to US energy independenceGolden, ColoradoOctober 2006
Electrochemical Engineering Research Lab, Ohio University 2
• Background
• How to get energy out?
• Ammonia Electrolysis
– Electrolysis of ammonia effluents
– Hydrogen Production
• Economic Analysis
• Conclusions
• Future Work
Outline
Electrochemical Engineering Research Lab, Ohio University 3
• All mammals (human and animal) produce liquid andsolid waste which contains considerable “undigested”energy
• Extensive activity ongoing worldwide in extractingresidual energy from solids. Most visible example isanaerobic digesters, but biomass gasification andanaerobic pyrolysis (destructive distillation) also viable.
• Little R&D effort in capturing the residual energy in liquidwaste, which is largely in the form of ammonia andammonia compounds (e.g. urea)
• Mammal urine contains ~5% urea; average humanexcretes 3-5 liters of urine daily; average cow excretes5-7 gallons
Background
• Background
• How to get energyout?
• AmmoniaElectrolysis
– Effluents
– H2 Production
• Economic Analysis
• Conclusions
• Future Work
Electrochemical Engineering Research Lab, Ohio University 4
• Aqueous urea is chemically 2 parts NH3 and 1 part CO2
(overall about 8% hydrogen)
• Urea decomposes naturally at ambient temperatures toyield NH3 via urease bacteria action, but this is asluggish process
• Above 500F urea decomposes thermally very rapidly;this process used extensively in de-NOx (NH3 + NOx !N2 + H20)
• Urea also broken down in pressurized water reactors at~200C, but much of the energy in the urea is consumed
• Electrolysis of ammonia/urea solutions could provide alow-T, energy efficient way to get the energy out of urea
How to get energy out?
• Background
• How to get energyout?
• AmmoniaElectrolysis
– Effluents
– H2 Production
• Economic Analysis
• Conclusions
• Future Work
Electrochemical Engineering Research Lab, Ohio University 5
Ammonia Electrolysis: In Situ H2
Production
• Anode: Ammonia Oxidation
H2O
NH3
KOH
H2N2
0
3 2 22 6 6 6 E =-0.77 vs SHE
! !+ " + +NH OH N H O e
0
2 22 2 2 E 0.82 V vs SHE
! !+ " + =H O e H OH
0
3 2 22 3 E 0.059 V! + =NH N H
• Background
• How to get energyout?
• AmmoniaElectrolysis
– Effluents
– H2 Production
• Economic Analysis
• Conclusions
• Future Work
• Cathode: Water Reduction
• Overall Reaction
Electrochemical Engineering Research Lab, Ohio University 6
Comparison with Water Electrolysis
• Using Solar Energy at $0.214/kW-h
• Ammonia cost at $300 per ton metric
2.007.1Hydrogen Cost($/kg H2)
1.5533Energy (W-h/gH2)
NH3
ElectrolysisWater
Electrolysis
SAVING95% LOWER ENERGY
71 % CHEAPER H2
• Background
• How to get energyout?
• AmmoniaElectrolysis
– Effluents
– H2 Production
• Economic Analysis
• Conclusions
• Future Work
Theoretical (Thermodynamics) Calculations
Electrochemical Engineering Research Lab, Ohio University 7
Advantages of Technology
• Minimization of hydrogen storage problem
• Electrolytic on-board reforming
• Zero green house emissions
• Fuel Flexibility
• Low temperature operation
• Compatibility with renewable energy sources (e.g. solar, wind)
• Fertilizer plants, municipal waste water treatment stations, andmodern engineered dairy/hog/poultry farms could potentiallyproduce their own energy from waste
• Background
• How to get energyout?
• AmmoniaElectrolysis
– Effluents
– H2 Production
• Economic Analysis
• Conclusions
• Future Work
Electrochemical Engineering Research Lab, Ohio University 8
Technology Objectives
• Ammonia removal from wastewater
– Protect rivers, lakes and groundwater
– Protect atmosphere
– Reduce wastewater processing costs
• Efficient hydrogen generation
– In-situ energy production
– Renewable source
– Low-cost hydrogen
• Background
• How to get energyout?
• AmmoniaElectrolysis
– Effluents
– H2 Production
• Economic Analysis
• Conclusions
• Future Work
Electrochemical Engineering Research Lab, Ohio University 9
Project Vision
EnergyEnergy
NHNH33+H+H22OO
(Waste water)(Waste water)
Clean energy supplyClean energy supply
HydrogenHydrogen
Clean waterClean water
NN22
Ammonia
Electrolysis for the
Production of
Hydrogen
NH3 fromlivestock (lagoon)
Electrochemical Engineering Research Lab, Ohio University 11
Key Point: Electrolysis of Ammonia Effluents (why?)
Electrochemical Engineering Research Lab, Ohio University 12
Ammonia Air Emissions
• Over 5 Million Ton per year (2002)1
1. G. E. Mansell, "An Improved Ammonia Inventory for the WRAP Domain (FinalReport)", ENVIRON International Corporation, Report No. 415.899.0700, March 7
(2005)
Native Soils
32%
Fertilizer
28%
Wild Animals
3%
Domestic
3% Livestock
34%
US Ammonia Production(Million Ton per year)
•2000: 11.8
•2001: 9.1
•2002: 10.1
•2003: 8.8
•2004: 8.9
Electrochemical Engineering Research Lab, Ohio University 13
Ammonia Air Emissions
1. G. E. Mansell, "An Improved Ammonia Inventory for the WRAP Domain (FinalReport)", ENVIRON International Corporation, Report No. 415.899.0700, March 7
(2005)
US Ammonia Production(Million Ton per year)
•2000: 11.8
•2001: 9.1
•2002: 10.1
•2003: 8.8
•2004: 8.9
Fertilizer, livestock, anddomestic 3.25 Million
Ton per year1
36.5% of 2004annual production
Electrochemical Engineering Research Lab, Ohio University 14
Impact of Recovery of Effluents for H2
Production
• Assumptions
– Recovery of fertilizer, livestock, and residentialsources
– Use to power residential houses with a consumptionof 12,000 Kw-h per house
– Combination of solar panel with ammonia electrolyticcell (AEC)
• Impact
– Produce enough energy to power over 900,000residential houses per year if all ammoniaemissions captured from fertilizer, livestock, andresidential sources
– Minimization of 1% CO2 emissions coming from theresidential sector by replacing fossil fuels
• Background
• How to get energyout?
• AmmoniaElectrolysis
– Effluents
– H2 Production
• Economic Analysis
• Conclusions
• Future Work
Electrochemical Engineering Research Lab, Ohio University 15
• Design Electrodes capable of electrolyzingammonia at low concentrations
• Unknown kinetics at low concentrations ofammonia
• Unknown effect of contaminants present inwaste waters (urea, proteins, salts, suspendedsolids, etc)
• Durability/reliability/lifetime of cells andelectrodes
Challenges. Technologyimplementation
• Background
• How to get energyout?
• AmmoniaElectrolysis
– Effluents
– H2 Production
• Economic Analysis
• Conclusions
• Future Work
Electrochemical Engineering Research Lab, Ohio University 16
• Design and evaluate electrode materials toimprove kinetic performance at lowconcentrations of Ammonia
Objectives
• Background
• How to get energyout?
• AmmoniaElectrolysis
– Effluents
– H2 Production
• Economic Analysis
• Conclusions
• Future Work
Electrochemical Engineering Research Lab, Ohio University 17
Methodology
Electrochemical Engineering Research Lab, Ohio University 18
• Two different substrates tested
– Raney Nickel
– Carbon fibers
• Substrates plated with combinations of noblemetals for the electro-oxidation of ammonia
Methodology
Substrates
• Background
• How to get energyout?
• AmmoniaElectrolysis
– Effluents
– H2 Production
• Economic Analysis
• Conclusions
• Future Work
Electrochemical Engineering Research Lab, Ohio University 19
Testing Cell
H2
N2
Electrochemical Engineering Research Lab, Ohio University 20
Removal of Ammonia
Performance of Pt-Ir-Rh Electrode, Initial conditions 21.5 mM NH3 and 0.2M KOH
IMs
Fnmt
!!
!!=
Final NH3 concentration1.83 mM
13.82 h
13.78 h
Electrochemical Engineering Research Lab, Ohio University 21
Faradaic Efficiency and Conversion at 25 mA/cm2
100o f
o
C Cx
C
!= "
100f
t
m
m! = "
91.5%
91.8%
Where:
x: conversion of ammonia
Co: initial concentration of ammonia, mM
Cf: final concentration of ammonia, mM
!: ammonia faradaic efficiency
mf: final mass of ammonia, g
mt: theoretical mass of ammonia, g
Successfullydemonstrated
Electrochemical Engineering Research Lab, Ohio University 22
Key Point: Hydrogen Production, Ammonia as a Hydrogen Carrier
Electrochemical Engineering Research Lab, Ohio University 23
• Evaluate the Feasibility of the technology forDistributed Size Onsite Hydrogen Production(480 kg H2/day)
– Energy balance
– Economics analysis
Objectives
• Background
• How to get energyout?
• AmmoniaElectrolysis
– Effluents
– H2 Production
• Economic Analysis
• Conclusions
• Future Work
Electrochemical Engineering Research Lab, Ohio University 24
Energy Balance
Electrochemical Engineering Research Lab, Ohio University 25
Operating Options (Day): Theoretically
Air
Electrical Energy
NH3/KOH/H2O
OU
AMMONIA IN
SITU H2
GENERATOR
FUEL
CELL
H2
H2O
Heat
Electrical
Energy
33 W-h/g H2
1.55 W-h/g H2
N2
Electrochemical Engineering Research Lab, Ohio University 26
Operating Options (Night): theoretically
Electrical
Energy31 W-h/g H2
Electrical
Energy
NH3/KOH/H2OOU
AMMONIA IN
SITU H2
GENERATOR
FUEL
CELLH2
H2O
Heat
1.55 W-h/g H2
N2
AirNo H2 Storage
Is this feasible?
Electrochemical Engineering Research Lab, Ohio University 27
Energy Balance at 25 oC
-10
0
10
20
30
40
50
0.000 0.005 0.010 0.015 0.020 0.025 0.030 0.035 0.040
Hydrogen Mass Flow, g/h
En
erg
y,
Wh
/gH
2
Net Energy
Energy used by Ammonia
Electrolytic Cell
Energy produced by PEM
Fuel Cell
Energy used by a Water
Electrolyzer
Theoretical Energy used by
Ammonia Electrolytic Cell
1M NH3
5M KOH
Electrochemical Engineering Research Lab, Ohio University 28
Economics Analysis and Comparison with Other Technologies forDistributed Size Onsite Hydrogen Production (480 kg H2 per
day)
1. Same assumptions as the Hydrogen Economy by the National Academy ofScience
2. Cost of Ammonia $300 per Metric Ton
3. Cell Operating at 50 oC with 0.058 cell Voltage
4. Energy consumption of by electrolysis 1.55 Kw-h/kg of H2. 100% ElectricEfficiency
5. Electricity at $0.07 per kwh
CAPACITY: 480 kg H2 per dayANNUAL AVERAGE OPERATING LOAD: 90%
TOTAL CAPITAL COST $ 0.743 millionTOTAL VARIABLE COST $ 285,000 /year AMMONIA at $ 300 per ton ELECTRICITY at $ 0.07 per kwh
CAPITAL CHARGES: $ 20,000 /year
NH3 113.4 Kg/h
N2 per 93.2 Kg/h
Same assumptions as
reported by the National
Academy of Engineering
ELECTROLYZER
H2
TO 400 ATM
H2 STORAGETO 400 ATM7 HOURS AT
PEAK SURGE
H2
dispenser
to
vehicles
20 kg
H2/hr
Proposed System for
Distributed Power
Generation
Up to 1000 kg H2/
day
Electrochemical Engineering Research Lab, Ohio University 30
Economic Analysis at Current Operating Conditions
Electrochemical Engineering Research Lab, Ohio University 31
Testing Loop
NH3 Electrolytic
Cell
NH3/KOH/water
feed tank
KOH/water
feed tank
Electrochemical Engineering Research Lab, Ohio University 32
The Ammonia Electrolytic Cell
Electrochemical Engineering Research Lab, Ohio University 33
Optimization of AEC Performance
ResultsRundomized
Order
KOH
Concentration (M)
NH3
Concentration (M)
Current
(mA)
Temperature
(°C)
Power
Consumption
(W-h/gH2)
1 0.5 0.5 300 25 15.5
2 0.5 0.5 100 25 12.2
3 0.5 5 100 25 9.0
4 0.5 5 300 50 11.5
5 7 0.5 300 50 11.3
6 7 5 300 25 13.6
7 0.5 0.5 300 50 12.2
8 7 5 100 50 8.6
9 0.5 5 100 50 8.7
10 7 0.5 100 50 9.4
11 7 0.5 300 25 14.0
12 0.5 5 300 25 14.4
13 0.5 0.5 100 50 9.9
14 7 5 300 50 10.2
15 7 0.5 100 25 11.6
16 7 5 100 25 10.0
V=0.34 V
Energy
V=0.33 V
Electrochemical Engineering Research Lab, Ohio University 34
Comparison with Other Technologies for Distributed Size Onsite HydrogenProduction (480 kg H2 per day)
1. Same assumptions as the Hydrogen Economy by the National Academy ofScience
2. Cost of Ammonia $300 per Metric Ton
3. Energy consumption based on real laboratory data
4. Electricity at $0.07 per kwh
3.37
1.02
NH3
Electrolysis
(8.7 Kwh/kgH2. 18.5%
ElectricEfficiency
2.00
0.743
NH3
Electrolysis
(1.55 Kwh/kgH2. 100%Electric
Efficiency
3.51
1.85
Natural GasSteam
Reforming*
6.58Hydrogen Cost($/kg H2)
2.54CapitalInvestment(Million $)
WaterElectrolysis
(52.49 Kwh/kgH2. 75% Electric
Efficiency)
CurrentTechnologies
SAVINGS 8.2 % CHEAPER H2 than NG reforming
At $ 0.07 KWh
48.7% CHEAPER H2 than Water Electrolysis
Electrochemical Engineering Research Lab, Ohio University 36
Sensitivity Analysis
1. Cost of Power can change depending on the source
2. The cost of ammonia can change. If ammonia from waste is used, it isestimated that no charges will be involved
3. Current density: 25 mA/cm2
4. Cell Operating at 50 oC with 0.34 cell Voltage
Electrochemical Engineering Research Lab, Ohio University 37
0
1
2
3
4
5
6
7
0 50 100 150 200 250 300
Cost of Ammonia, $/ton metric
Cost
of
H2 f
rom
Am
mo
nia
Ele
ctro
lysi
s, $
/Kg
NH3 Electrolysis with Solar Energy, Current
Technology ($0.319 per KWh)
DOE Goal
NH3 Electrolysis with Solar
Energy, future optimism ($0.098 per KWh)
NH3 grid power, current
technology ($0.07 per KWh)
NH3 wind/turbine power,
current technology ($0.06 per KWh)
NH3 wind/turbine power, future
optimism ($0.04 per KWh)
Water Electrolysis= $28/kg
Water Electrolysis= $6.58/kg
Water Electrolysis= $6.18/kg
Electrochemical Engineering Research Lab, Ohio University 38
Conclusions
• Efficient removal of ammonia achieved
• Ammonia Electrolysis is much cheaper than waterelectrolysis
• The ammonia electrolytic cell can operated with any sourceof renewable energy
• H2 can be produced at less than $2.00 per Kg for distributedpower
• The economic feasibility of the technology for distributedpower has been demonstrated
• The key for the process is to use ammonia from waste. Inwhich case, up to $100 per ton metric of ammonia can bespent to purify the waste stream if needed.
• Ammonia electrolysis may be even cheaper as NO hydrogenstorage tanks NEEDED.
Electrochemical Engineering Research Lab, Ohio University 39
Farm of the Future
Lagoon
Pretreatment and
Electrolyte Recovery
Units
Sun
Solar
panels
Bench scale AEC PEM fuel cell Fan power by PEM
fuel cell
Lagoon
Pretreatment and
Electrolyte Recovery
Units
Sun
Solar
panels
Bench scale AEC PEM fuel cell Fan power by PEM
fuel cell
Electrochemical Engineering Research Lab, Ohio University 40
Future Work
• Improve efficiency of theprocess
• Determine reaction rate toscale up and design AECto pilot scale to determinemore accurate costs
• Determine energyefficiency of Power Source(integrated AEC/PEM fuelcell)
• Define pre-treatment unitsto use ammonia fromwaste
Lagoon
Pretreatment and
Electrolyte Recovery
Units
Sun
Solar
panels
Bench scale AEC PEM fuel cell Fan power by PEM
fuel cell
Lagoon
Pretreatment and
Electrolyte Recovery
Units
Sun
Solar
panels
Bench scale AEC PEM fuel cell Fan power by PEM
fuel cell
Electrochemical Engineering Research Lab, Ohio University 41
Acknowledgements
• Army Research Office (DURIP award)
• NSF Path Award
• 1804 Fund Award by the Trustees of the Ohio UniversityFoundation Office of the Vice-President for Research, OhioUniversity
• Student Enhancement Award (Office of the Vice-President forResearch, Ohio University)
• Dr. Ingram Department of Physics, Ohio University
Electrochemical Engineering Research Lab, Ohio University 42
The EERL Group
For more information visit:http://webche.ent.ohiou.edu/eerl/
www.ohio.edu/engineering
Contact:Gerri Botte at [email protected]